The problem it solves
The rotator cuff holds the ball centred in the socket and allows the deltoid to lift the arm. When the cuff is irreparably torn, that mechanism fails: the ball rides upwards, the shoulder loses the ability to elevate — a “pseudoparalytic” shoulder — and arthritis often follows. This combination is cuff tear arthropathy.
An anatomic replacement cannot solve this. Without a cuff to centre it, the ball levers against the new socket and loosens it.
How reversing it works
Reverse total shoulder replacement (rTSA) does something elegant: it swaps the ball and socket. A metal ball is fixed to the glenoid and a socket to the humerus.
This moves the centre of rotation inward and downward, which lengthens the deltoid’s lever arm and allows that muscle alone to elevate the arm — no rotator cuff required. It also makes the joint inherently more stable, since the ball is now captured within the socket.
Who it suits
- Cuff tear arthropathy — the original and principal indication
- Irreparable rotator cuff tears with loss of active elevation, even without much arthritis
- Complex proximal humeral fractures in older patients, where reconstructing the tuberosities is unreliable
- Failed previous shoulder replacement, or arthritis with severe glenoid bone loss
- Revision of an anatomic replacement whose cuff has failed
The trade-off is honest: reverse replacement is superb at restoring elevation and abolishing pain, but rotation — reaching behind your back or across your body — is often less well restored than after an anatomic replacement. Where the cuff is intact, anatomic remains the better functional operation.
What the evidence shows
- Survivorship matches anatomic replacement. Multi-registry data reports 93.1%–98.9% survival at five and eight years, drawn from more than 7,700 reverse replacements.
- Revision rates are low and comparable — approximately 2.2%, with a surgical complication rate of around 9.9%, essentially the same as anatomic replacement.
- Reverse has become the more commonly performed of the two, and its indications have widened considerably beyond cuff tear arthropathy.
- But wider is not always better. New Zealand registry data (2026) found that in inflammatory arthritis, anatomic replacement achieved better function with equivalent survivorship — a caution against choosing reverse simply because it is more forgiving.
The surgery and recovery
- General anaesthesia, usually with a nerve block
- Hospital stay is typically one to two nights
- A sling is worn in the early weeks
- Rehabilitation is often simpler than after anatomic replacement, because there is no subscapularis repair to protect — movement can usually begin earlier
- Most patients are substantially comfortable by 6–12 weeks, with improvement continuing to around 12 months
- Driving is usually possible at about six weeks
Specific risks discussed at consultation include dislocation, acromial stress fracture, infection and nerve injury.
Is it right for me?
Reverse replacement is the right answer when the rotator cuff cannot be relied upon — and in that setting it is transformative, restoring the ability to lift the arm to patients who had lost it. Where the cuff is intact, the decision deserves more thought, because anatomic replacement usually gives a more natural shoulder. That assessment is what your consultation is for.
Mako robotic-assisted shoulder surgery
Following the initial trial at the Wesley Hospital, Dr Melsom plans to offer Mako-assisted reverse shoulder replacement to suitable patients. Robotic assistance adds guidance during socket preparation to the existing 3D planning process. Read how Mako compares with planning and patient-specific guides, and what the evidence can tell us.